The present invention relates generally to stereoscopic viewing devices imparting a three dimensional image to a user.
Briefly, binocular stereoscopic viewing devices function to impart slightly different images to each of the viewer's eyes resulting in the mental image being three dimensional. Early hand held stereoscopic viewers with a separate photograph provided for viewing by each eye were cumbersome and of limited usefulness. More recent efforts have included stereoscopic motion pictures using two interaxially spaced cameras or a single camera with a stereo lens. Colored filters code the separate views and require the viewer to wear glasses each lens of which is a different color to block the image intended for viewing only by the other eye. This system is termed in the art the anaglypic technique. A similar three dimensional system uses polarized lenses in the glasses worn by the viewer where an image for one eye is blocked from viewing by the other eye by a polarizing filter in a lens. A still further stereoscopic system is termed lenticular three dimensional viewing where a screen onto which the moving picture is projected is lenticular to separate the images projected by a "left eye projector" and a "right eye projector".
For certain reasons no one stereoscopic system has been widely or commercially accepted with use to date being more or less on an experimental basis. It is suspected that the added costs of stereoscopic filming and projecting coupled with the tiring effect on the eyes of three dimensional glasses have all discouraged further efforts.
U.S. Pat. No. 946,339 is of interest for the reason it shows a stereoscope capable of providing separate paths of light waves to a viewer's eyes. The prisms used are fixedly mounted in the device. U.S. Pat. No. 366,823 shows a stereoscope having swingably positionable "shutters" to regulate the path of light to each eye. U.S. Pat. No. 2,709,401 discloses laterally adjustable planar mirrors. U.S. Pat. No. 2,845,844 shows pairs of mirrors each pair serving to deflect light waves through 180 degrees to each of the viewer's eyes.